REDHAT-BUG-1344251
First published: Thu Jun 09 2016(Updated: )
It was found that original patch for issues <a href="https://access.redhat.com/security/cve/CVE-2015-1283">CVE-2015-1283</a> and <a href="https://access.redhat.com/security/cve/CVE-2015-2716">CVE-2015-2716</a> used overflow checks that could be optimized out by some compilers applying certain optimization settings, which can cause the vulnerability to remain even after applying the patch. One pattern in the fix for CVE-2015-1283/CVE-2015-2716 is: /* bufferSize is positive here */ do { bufferSize *= 2; } while (bufferSize < neededSize && bufferSize > 0); if (bufferSize <= 0) { errorCode = XML_ERROR_NO_MEMORY; return NULL; Any of the modern optimizing compiler, IF able to infer that bufferSize is initially positive (which is true but not obvious to see through local reasoning), will eliminate bufferSize > 0 as always true when the execution is defined, and bufferSize <= 0 as always false when the execution is defined. Without knowing that bufferSize starts positive, an optimizing compiler could also move the test bufferSize > 0 out of the loop, that is, compile the code as if it had been written: if (bufferSize <= 0) errorCode = XML_ERROR_NO_MEMORY; return NULL; else { do { bufferSize *= 2; } while (bufferSize < neededSize); } Both cases leads to not eliminating the vulnerability. Upstream patch: <a href="https://sourceforge.net/p/expat/code_git/ci/f0bec73b018caa07d3e75ec8dd967f3785d71bde/tree/expat/lib/xmlparse.c?diff=a238d7ea7a715ef3850c4cbdd86aeda7077b6bbc">https://sourceforge.net/p/expat/code_git/ci/f0bec73b018caa07d3e75ec8dd967f3785d71bde/tree/expat/lib/xmlparse.c?diff=a238d7ea7a715ef3850c4cbdd86aeda7077b6bbc</a>
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Oracle Expat |
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Reference Links
- https://access.redhat.com/security/cve/CVE-2015-1283
- https://access.redhat.com/security/cve/CVE-2015-2716
- https://sourceforge.net/p/expat/code_git/ci/f0bec73b018caa07d3e75ec8dd967f3785d71bde/tree/expat/lib/xmlparse.c?diff=a238d7ea7a715ef3850c4cbdd86aeda7077b6bbc
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1344253
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1344252
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1344254
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1344256
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1344255
- https://bugzilla.redhat.com/show_bug.cgi?id=1344251
Frequently Asked Questions
What is the severity of REDHAT-BUG-1344251?
The severity of REDHAT-BUG-1344251 is considered high due to potential overflow vulnerabilities affecting the parsing functionality.
How do I fix REDHAT-BUG-1344251?
To fix REDHAT-BUG-1344251, users should update to the latest version of the Expat library that addresses the overflow issues.
What versions of Expat are affected by REDHAT-BUG-1344251?
All versions of Expat prior to the patched release addressing REDHAT-BUG-1344251 are affected.
What vulnerabilities are related to REDHAT-BUG-1344251?
REDHAT-BUG-1344251 is related to CVE-2015-1283 and CVE-2015-2716, which both involve security risks associated with buffer overflows.
Is there a workaround for REDHAT-BUG-1344251?
As of now, the recommended action is to apply the latest patches as no specific workaround exists for REDHAT-BUG-1344251.
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